我想将w x h的uint32_t图像数据转换为uint8_t图像。我应该如何转换图像。我想将leptonica的PIX转换为opencv Mat。
我想知道使用Bitwise运算符的困难方法。像素打包为AARRGGBB。
另外我想转换
cv:Mat 8UC1到PIX。 即8位单通道图像到32位图像。或者,如果你能想到任何其他方式来进行排序。
答案 0 :(得分:1)
如果您想获得包含数据的4通道RGBA图像,可以尝试将每个uint32_t转换为4个无符号字符数。有关如何执行此操作的讨论,请参阅Converting an int into a 4 byte char array (C)。
完成此操作后,您只需使用所获得的数据创建cv::Mat
类型CV_8UC4
。
答案 1 :(得分:1)
uint32_t * imData = yourImageDataPointer;
uchar * reinterpretedData = (uchar*)imData;
cv::Mat cvImage = cv::Mat(h,w, CV_8UC4);
cv::Mat bgr; // displayable image without alpha channel
cv::cvtColor(cvImage, bgr, CV_RGBA2BGR);
cv::imshow("img", bgr);
cv::waitKey (0);
请尝试此操作并发布结果图片,如果它不符合您的预期
答案 2 :(得分:1)
以下是将cv :: Mat转换为leptonicas 32bit PIX格式的答案:
PIX* toPIX(const cv::Mat& img)
{
if(img.empty())
throw std::invalid_argument("Image is empty");
//PIX has got 4 channels hence we need to add one
//more channel to this image
cv::Mat alphaImage;
if(img.type() == CV_8UC3) {
cv::cvtColor(img,alphaImage,cv::COLOR_BGR2RGBA);
} else if(img.type() == CV_8UC1) {
cv::Mat gray = img.clone();
std::vector<cv::Mat> channelsPlusAlpha;
//construct 4 channel by reapeating gray across 3 channels and filling alpha with constant value
channelsPlusAlpha.push_back(gray);//channels[2]);//R
channelsPlusAlpha.push_back(gray);//channels[1]);//G
channelsPlusAlpha.push_back(gray);//channels[0]);//B
channelsPlusAlpha.push_back(cv::Mat(img.size(),CV_8UC1,cv::Scalar::all(255)));//A
cv::merge(channelsPlusAlpha,alphaImage);
} else {
throw std::logic_error("Image type undefined");
}
//Prepare PIX
int w = alphaImage.cols;
int h = alphaImage.rows;
int bpl = alphaImage.step1();//bytes per line
int bpp = alphaImage.channels();//bytes per pixel
int top = 0; //x (0,0) or if we want to deal with sub image then those coordinates have to be fed
int left = 0;//y
uchar* image_data = alphaImage.data;
//Create PIX
PIX *pix = pixCreate(w,h,32);
uint32_t* data = pixGetData(pix);
int wpl = pixGetWpl(pix);//get the words per line
const uint8_t* imagedata = image_data + top * bpl + left * bpp;
for(int y=0; y < h; ++y) {
const uint8_t* linedata = imagedata; // linescan
uint32_t* line = data + y *wpl;
for(int x =0; x < w; ++x) {
line[x] = (linedata[0] << 24) |
(linedata[1] << 16) |
(linedata[2] << 8) |
linedata[3];
linedata += 4;
}
imagedata += bpl;
}
return pix;
}